This paper presents a neurosurgical device called NEIT 2 (Nerve Electrode Insertion Tool) to implant a 3D microelectrode array into a peripheral nervous system. Using an elastomer-made nerve holder, the device is able to stable target a flexible nerve, and then safely inserts an electrode array into the fixed nerve. Finally, a nerve containment assembly is made at once. We conducted animal experiments to evaluate the proposed scenario using a 3D printed prototype and commercial microelectrodes. The results show that microelectrodes are successfully implanted into sciatic nerves of rats and neural signals are recorded through the chronically implanted electrodes.